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Preparation process of 3,3-dimethyl-4-pentenoic acid methyl ester

A technology for the preparation of methyl pyretinate, which is applied in the field of preparation of methyl pyretinate, can solve the problems of the loss of pyretinic acid, reduce the yield, and high production cost, and achieve the effect of increasing the yield and high product purity

Inactive Publication Date: 2009-10-28
NANTONG TENDENCI CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are following problems in the purification method adopted both at home and abroad: a few steps of reaction are added, which greatly reduces the yield; during saponification and acidification, water is introduced, and the cardycin is separated by liquid separation, which causes the loss of the cardynic acid; Introduced water in the reaction, it is difficult to ensure that the moisture in the methyl bentinate is less than 500PPm (moisture has an impact on the subsequent reaction catalyst); the equipment investment has been increased; repeated use of sulfuric acid has seriously corroded the equipment; the production cost is high

Method used

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  • Preparation process of 3,3-dimethyl-4-pentenoic acid methyl ester
  • Preparation process of 3,3-dimethyl-4-pentenoic acid methyl ester
  • Preparation process of 3,3-dimethyl-4-pentenoic acid methyl ester

Examples

Experimental program
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Effect test

Embodiment 1

[0023] The molar ratio of reactants is trimethyl orthoacetate: isopentenol: catalyst = 1: 0.3: 0.02, add a certain amount of trimethyl orthoacetate, pump in the catalyst phosphoric acid \ sodium alkoxide and raise the temperature to 85 °C and start to drop isoamyl For pentenol, the dropping time is controlled within 5 hours. After the dropping is completed, the temperature of the kettle rises to about 95°C, and at the same time, it continues to receive the fore distillation with a top temperature <45°C. The reaction time is 3 hours at 90°C, and then the temperature of the kettle is gradually raised to about 100°C in 5 hours. In 12 hours, speed up the collection of the second distillate, which takes about 6 hours. When the second distillate is received, the temperature of the kettle is about 120~125°C. After the reaction is completed, the temperature is lowered, and then the material is fed to the crude ester crude product storage tank for rectification. The molar yield that ob...

Embodiment 2

[0025] The molar ratio of the reactants is trimethyl orthoacetate: isopentenol: catalyst = 1:0.5:0.03, add a certain amount of trimethyl orthoacetate, pump in the catalyst phosphoric acid\sodium alkoxide and raise the temperature to 80°C to start adding isoamyl For pentenol, the dropping time is controlled within 6 hours. After the dropping is completed, the temperature of the kettle rises to about 100°C, and at the same time, it continues to receive the fore distillation with a top temperature <45°C. The reaction time is 2 hours at 95°C, and then the temperature of the kettle is gradually raised to about 105°C in 6 hours. After holding for 4 hours, the second fraction is received, the top temperature is gradually raised to about 100°C, and the temperature of the kettle is gradually raised to about 135°C. Time control In 12 hours, speed up the collection of the second distillate, which takes about 6 hours. When the second distillate is received, the temperature of the kettle is...

Embodiment 3

[0027] The molar ratio of the reactants is trimethyl orthoacetate: isopentenol: catalyst = 1:0.4:0.05, add a certain amount of trimethyl orthoacetate, pump in the catalyst phosphoric acid\sodium alkoxide and raise the temperature to 82°C and start to drop the isoamyl For pentenol, the dropwise addition time is controlled within 4 hours. After the dropwise addition, the temperature of the kettle rises to 95°C, and at the same time, it continues to receive the fore distillation with a top temperature <45°C. The reaction time at 100°C is 4 hours, and then the temperature of the kettle is gradually raised to about 100°C in 5 hours. After holding for 5 hours, the second fraction is received, the top temperature is gradually raised to about 100°C, and the temperature of the kettle is gradually raised to about 135°C. Time control In 12 hours, speed up the collection of the second distillate, which takes about 6 hours. When the second distillate is received, the temperature of the kett...

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Abstract

The invention discloses a preparation process of 3,3-dimethyl-4-pentenoic acid methyl ester, comprising the following steps: heating and reflowing prenol and trimethyl orthoacetate under the existence of a catalyst to obtain methyl alcohol and excessive trimethyl orthoacetate, and the then raising the temperature to produce the 3,3-dimethyl-4-pentenoic acid methyl ester after Clisen rearrangement reaction. The process adopts a novel composite catalyst, improves the yield of the 3,3-dimethyl-4-pentenoic acid methyl ester and has high product purity which is generally over 99 percent.

Description

technical field [0001] The present invention relates to a kind of preparation technology of methyl benzinate. Background technique [0002] Methyl bentinate is an important intermediate in the synthesis of DV-methyl chrysanthemum, which can be used to synthesize many hygienic and medical pyrethroid insecticides. There are following problems in the purification method adopted both at home and abroad: a few steps of reaction are increased, which greatly reduces the yield; during saponification and acidification, water is introduced, and the cardycin is separated by liquid separation, which causes the loss of the cardycin; Introduced water in the reaction, it is difficult to guarantee that the moisture in the methyl bentinate is less than 500PPm (moisture has an impact on the subsequent reaction catalyst); the equipment investment has been increased; repeated use of sulfuric acid has seriously corroded the equipment; the production cost is high. Contents of the invention [...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/533C07C67/03
Inventor 查志明
Owner NANTONG TENDENCI CHEM
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